Today most computer users interact with the machine by way of a graphical user interface which, by exploiting the computer's visual display and intuitive input devices such as the mouse, mediates access to the operating system, application programs, and stored data. The standard approach to the design of the user interface has relied on a simple visual metaphor in which data files are contained in folders organized within a hierarchically-structured file system tree. The user interface provides controls that permit the user to navigate through the file system tree in order to locate and act upon data. Moreover, these existing structures allow a user to navigate through a tree-like structure containing multiple nested nodes. FIG. 2 illustrates an exemplary prior art tree-like structure.
The real-world familiarity of the file/folder model of storage contributed to its acceptance and popularity among computer users, but such user interfaces were also successful because users typically stored a relatively small number of data files on their machines. The ease with which computer systems can now be used, coupled with the availability of massive amounts of inexpensive disk storage, have to some degree made the standard data storage interface a victim of its own success. Computers are now being used to store large quantities of personal data in a variety of different formats for use with many different applications. It is not uncommon for a user to have hundreds or thousands of text documents, photographs, audio files, and other data records stored across multiple hard disks, shared networks and other storage media. Frequently the expanded quantity of data items are nested in a hierarchy of node levels in a tree-like structure. Given such a development, drawbacks to the conventional folder tree storage model have become evident to computer users. In particular, the growth in the amount of data stored by users has made navigating through data less efficient and more cumbersome.
Although such prior art systems are easier to use than the command-line shell interfaces that preceded them, they can create a hardship for a user when navigating through the structure when these tree structures become deeply nested (e.g., a tree with a multiplicity of node levels). For example, these prior art folder tree structures are not user-friendly in that they distract a user by requiring the user to scroll horizontally as the user navigates from a root node to nodes in the folder tree that are deeply nested. Likewise, prior art folder tree structures reduce a user's efficiency by requiring a user to scroll horizontally as the user vertically navigates from deeply nested nodes in a folder tree towards a root node, or vice versa. Furthermore, prior art tree structures sometimes leave a user “blind” as the user navigates through node levels in a tree structure because the relevant node descriptor may lay outside the visible area of a narrow window, e.g., items 208 in FIG. 2.
There is no general mechanism for navigation comparable in ease and efficiency of use as the file system Explorer tree of released versions of Microsoft® Windows® brand operating systems. Therefore, there is a need in the art for a mechanism that would increase the efficiency of a user during navigation through a hierarchical structured file system tree displayed in a window with a narrow viewable area in one dimension. More generally, there is a need in the art for a mechanism of a technical nature for use with any navigational control that eliminates the burden on a user to navigate in a second dimension as a user traverses in a first dimension through the navigational control. Furthermore, it would be a technical advancement in the art to provide a novel user interface that enhances user efficiency (e.g., reduces the input required of a user) to navigate through a folder tree or other navigational control structure.